Flow cytometry techniques to size individual fragments of DNA and analyze other small biological particles are under development. During the past year, it was discovered that the dye being used has a small dynamic range requiring reasonably accurate knowledge of DNA concentrations prior to staining. A new dye, Pico Green has been found to have a much wider dynamic range alleviating the need to precisely know the DNA concentration prior to analysis. Current efforts are focused on applying the technology to bacterial species and strain identification. Details are contained in the Project 3 progress report and Research Highlight Bacterial Fingerprinting by Flow Cytometry Bacterial Species Discrimination.